iTools 8.2 contains a new updated version of Apache, Apache 2.2. Apache
2.2 has significant internal changes to support higher performance and better
organization, allowing for future growth. One major performance change is memory
and disk HTTP page caching. In previous Apache versions, memory and disk caching
only partially worked. This has been fixed, and now both memory and, to a lesser
extent, disk caching provide a significant performance boost to overall operations.

There are three changes, however, that you will need to consider when upgrading
iTools: new module APIs, new authentication methods, and new configuration
file structure.

Apache module APIs

Apache 2.2 has a new Apache module API. The modification is not backward compatible
so all Apache modules have to be rebuilt. This means that new versions of PHP,
MySQL, Tomcat and others are required when moving to iTools 8.2.

Apache Authorization & Authentication

Apache authorization and authentication has been significantly enhanced.
The main externally visible change for iTools users is in the area of realm
authentication. Previously the 'AuthDBMAuthoritative On' directive was used
as a fixed part of the realm authentication. This directive has been removed.
In its place a new directive 'AuthBasicProvider dbm' has been installed.
So in each place where an 'AuthDBMAuthoritative On' is found in the Apache
configuration, it must be replaced with an 'AuthBasicProvider dbm'.

Apache Configuration

The third change has an even larger impact on users that are upgrading to
the new version. The format of the standard Apache httpd.conf configuration
file has changed. The httpd configuration file has been broken into a main
single file with about ten smaller constituent files, each containing Apache
directives specific to an area of Apache configuration. The constituent files
are kept in a sub-directory of the main Apache configuration directory called "extra" and
are included into the new main httpd.conf with Apache "Include" directives.
For example, the file extra/httpd-mpm.conf contains all of the Apache directives
pertaining to worker thread populations. Perusing the extra directory will
give you a feel for the new files and the Apache directives that have been
distributed to them.

The impact of this on iTools is that there is no programmatic way to upgrade
an old httpd.conf file to the new format. When an iTools 8.2 upgrade is installed,
the previous version of the httpd.conf file is saved in httpd.conf.PREVIOUS_COPY
and a standard version of the new Apache 2.2 httpd.conf is installed. iTools
has separate vhost specific configuration into a secondary set of host-by-host
configuration files for some time now (and Apache 2.2 has embraced this organization),
so the upgrade will not impact vhost configuration, however there are directives
that were previously stored in the httpd.conf file that must be moved to
one of the extra constituent files. Therefore, after an iTools upgrade the
PREVIOUS_COPY httpd.conf file must be hand-edited and Apache configuration
directives must be installed in the new Apache 2.2 httpd.conf.